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The effect of foliar treatment with jasmonic acid at 0.5 mM (JA) and biochar (15 ton ha−1) as a soil amendment for the faba bean (Vicia faba L. Sakha 4) was studied under salinity conditions. Salt stress led to a significant decrease in leaf numbers, leaf areas and plants, chlorophyll content, relative water content, and yield parameters. In contrast, reactive oxygen species, the proline concentration, level of malondialdehyde, and amount of electrolyte leakage were noticeably increased during both seasons under salt levels of 1500 and 3000 ppm sodium chloride (NaCl). Also, enzyme activities (i.e., of superoxide dismutase, catalase, peroxidase, and glutathione reductase) were increased, especially under a high level of salinity stress (3000 ppm). Application of biochar, jasmonic acid, or biochar + jasmonic acid significantly reduced the catalase, superoxide dismutase, and glutathione reductase activities in salt-stressed plants to values approaching those of the control (unstressed) plants, especially under 1500 ppm of NaCl stress. Biochar and jasmonic acid treatments mitigated the damaging effects of salinity and improved the plant status as indicated by the plant height, leaf area, relative water content, and chlorophyll a and b concentrations. Moreover, biochar and jasmonic acid treatments of the salt-stressed plants enhanced plant productivity, number of flowers, number of seeds per plant, and weight of 100 seeds during two successive seasons. Overall, this study suggests that biochar or jasmonic acid treatments might be promising for mitigating the detrimental impact of salt stress on faba beans.

Generally, under normal conditions plants are resistant to many of the incompatible pathogens (viral, fungal and bacterial), and this is named “non-host resistance phenomenon”. To understand this phenomenon, different types of food crops (faba bean, squash, barley and wheat) were inoculated with compatible and incompatible pathogens. Strong resistance symptoms were observed in the non-host/incompatible pathogen combinations as compared with host/compatible pathogen combinations, which showed severe infection (susceptibility). Reactive oxygen species (ROS) mostly hydrogen peroxide and superoxide were significantly increased early 24 and 48 h after inoculation (hai) in the non-host plants comparing to the host. Antioxidant enzymes activity (catalase, polyphenol oxidase and peroxidase) were not increased at the same early time 24, 48 hai in the non-host resistant and host resistant plants, however, it increased later at 72 and 168 hai. Electrolyte leakage decreased significantly in non-host resistant and host resistant/pathogen combinations. Catalase and peroxidase genes were significantly expressed in non-host resistant and in host resistant plants as compared to the host susceptible one, which did not show expression using RT-PCR technique. Furthermore, Yr5, Yr18 and Yr26 resistant genes were identified positively using PCR in all treatments either host susceptible or non-host resistant plants in which prove that no clear role of these resistant genes in resistance. Early accumulation of ROS could have a dual roles, first role is preventing the growth or killing the pathogens early in the non-host, second, stimulating the gene appearance of related genes in addition the activition of antioxidant enzymes later on which thereby, neutralize the harmful effect of ROS and consequently suppressing disease symptoms. The new finding from this study supporting the plant breeders with new source of resistance to develop new resistant cultivars and/or stop the breakdown of resistance in resistant cultivars. Keywords: Non-host resistance, Reactive oxygen species, Antioxidants, Gene expression

Garlic is an important vegetable in terms of its economic value and also as a medicinal plant. In this study, chitosan (300 mM) and yeast extract (8 g/L) were used individually or in combination to improve the yields of garlic plants under drought conditions (i.e., 75% and 50% of the water they would normally receive from irrigation) for two seasons. Significant decreases in numbers of leaves per plant and plant height, plant dry weight, relative water content, and chlorophyll a and b concentrations were found in stressed garlic plants in both seasons. The greatest reductions in these characters were recorded in plants that received only 50% of the normal irrigation in both seasons. Levels of hydrogen peroxide, products of lipid peroxidation such as malondialdehyde, and superoxide, as well as percentages of electrolyte leakage, were elevated considerably and were signals of oxidative damage. The application of the yeast extract (8 g/L) or chitosan (300 mM) individually or in combination led to a remarkable increase in the most studied characters of the stressed garlic plants. The combination of yeast extract (8 g/L) plus chitosan (300 mM) led to increase plant height (44%), ascorbic acid levels (30.2%), and relative water content (36.8%), as well as the chlorophyll a (50.7%) and b concentrations (79%), regulated the proline content and levels of antioxidant enzymes in stressed garlic plants that received 75% of the normal irrigation, and this decreased the signs of oxidative stress (i.e., percentage of electrolyte leakage and levels of malondialdehyde, hydrogen peroxide, and superoxide).

In the present investigation, we study the effect of Bacillus thuringiensis MH161336 (106–8 CFU/cm3), silicon (25 mL L−1), and carrot extract (75 mL L−1) as seed primers, individually or in combination, on morphological, physio-biochemical and yield components of drought-stressed pea plants (Master B) during 2019/2020 and 2020/2021 seasons. Our results indicated that drought causes a remarkable reduction in plant height, leaf area, number of leaves per plant, and number of flowers per plant in stressed pea plants during two seasons. Likewise, number of pods, pod length, seeds weight of 10 dried plants, and dry weight of 100 seeds were decreased significantly in drought-stressed pea plants. Nevertheless, seed priming with the individual treatments or in combination boosted the morphological, physio-biochemical, and yield characters of pea plants. The best results were obtained with the Bacillus thuringiensis + carrot extract treatment, which led to a remarkable increase in the number of leaves per plant, leaf area, plant height, and number of flowers per plant in stressed pea plants in both seasons. Moreover, pod length, number of seeds per pod, seeds weight of 10 dried plants, and dry weight of 100 seeds were significantly increased as well. Bacillus thuringiensis + carrot extract treatment led to improved biochemical and physiological characters, such as relative water content, chlorophyll a, chlorophyll b, regulated the up-regulation of antioxidant enzymes, increased seed yield, and decreased lipid peroxidation and reactive oxygen species, mainly superoxide and hydrogen peroxide, in drought-stressed pea plants.

Greenhouse experiments were conducted to evaluate the utilization of compost derived from grape fruit waste (GFW) as an ingredient in nursery substrates for germination and development of c...

Leaf rust caused by Puccinia triticina f.sp. tritici is the most important serious diseases attacking wheat plants. The efficacy of bioagents, i.e. Bacillus subtilis, Bacillus chitinospours, Bacillus pumilus, Trichoderma viride and Trichoderma harzianum to control leaf rust was studied. The bioagents were sprayed before and after inoculation with P. triticina by 24 h during 2016/17 and 2017/18 growing seasons. Our results showed that, B. subtilis was the best treatment followed by T. viride, where there were significant increase in incubation and latent periods of the pathogen as well as increase 1000 kernel weight (g) and yield/plot (kg). On contrary, there was significant decrease in number of pustules, pustule length, pustule width, final rust severity (%) and area under disease progress curve (AUDPC). Additionally, the treatments led to increase activity of catalase (CAT) and peroxidase (POX), however, electrolyte leakage was decreased compared to control. Correlation analysis gave evidence to the importance of FRS (%) as the good indicator for the study efficacy of different bioagents on control leaf rust. Application of bioagents as a source for wheat leaf rust disease control are safe on the environment in addition to the pathogen creates strains resistant to fungicides.

The resistant, slow and fast-rusting cultivars were selected from 15 wheat cultivars to study biochemical and histological aspects of compatible and incompatible wheat-Puccinia striiformis interactions. Final rust severity (%) and area under disease progress curve were significantly decreased in resistant cultivars compared with susceptible ones. Biochemical analysis revealed that reactive oxygen species (ROS), i.e. superoxide (O2•-) and hydrogen peroxide (H2O2) significantly accumulated in the susceptible cultivars. While, activities of catalase (CAT), peroxidase (POX) and chlorophyll concentrations were increased in resistant cultivars. Histological examination using scanning and transmission electron microscope indicated that approximately all haustoria and hyphae were inhibited in resistant cultivar (Misr-1), development of haustorial mother cells and haustoria were retarded, and they were abnormal. On the other hand, large amounts of intercellular hyphae presented in the intercellular spaces and many haustoria were produced in fast-rusting cultivar (Sids-12). Nevertheless, a little of sours and spores on upper epidermis and in mesophyll tissue were observed in slow-rusting cultivar (Sakha-93)..

Salinity stress is one of the major environmental constraints responsible for a reduction in agricultural productivity. This study investigated the effect of exogenously applied nitric oxide (NO) (50 μM and 100 μM) in protecting wheat plants from NaCl-induced oxidative damage by modulating protective mechanisms, including osmolyte accumulation and the antioxidant system. Exogenously sourced NO proved effective in ameliorating the deleterious effects of salinity on the growth parameters studied. NO was beneficial in improving the photosynthetic efficiency, stomatal conductance, and chlorophyll content in normal and NaCl-treated wheat plants. Moreover, NO-treated plants maintained a greater accumulation of proline and soluble sugars, leading to higher relative water content maintenance. Exogenous-sourced NO at both concentrations up-regulated the antioxidant system for averting the NaCl-mediated oxidative damage on membranes. The activity of antioxidant enzymes increased the protection of membrane structural and functional integrity and photosynthetic efficiency. NO application imparted a marked effect on uptake of key mineral elements such as nitrogen (N), potassium (K), and calcium (Ca) with a concomitant reduction in the deleterious ions such as Na+. Greater K and reduced Na uptake in NO-treated plants lead to a considerable decline in the Na/K ratio. Enhancing of salt tolerance by NO was concomitant with an obvious down-regulation in the relative expression of SOS1, NHX1, AQP, and OSM-34, while D2-protein was up-regulated.

Simple Summary Among abiotic stress factors, drought is one of the most detrimental factors in arid and semiarid regions, causing a significant decrease in plant growth and yield in most species, including crops. Under drought conditions, morphological, physiological and biochemical characteristics such as plant height and enzymatic activities are negatively affected. This negative effect may be alleviated with the aid of plant growth-promoting bacteria. Application of plant growth-promoting bacteria such as Paenibacillus, Azospirillum, Rhizobium, Bacillus, Azotobacter, Klebsiella, Pseudomonas and Serratia can enhance hormonal balance, maintain nutrient status and improve plant growth characters as well as increase yield. This review discusses the pivotal role of plant growth-promoting bacteria in mitigating drought stress by improving plant growth characters and yield. Abstract Plant growth-promoting bacteria play an essential role in enhancing the physical, chemical and biological characters of soils by facilitating nutrient uptake and water flow, especially under abiotic stress conditions, which are major constrains to agricultural development and production. Drought is one of the most harmful abiotic stress and perhaps the most severe problem facing agricultural sustainability, leading to a severe shortage in crop productivity. Drought affects plant growth by causing hormonal and membrane stability perturbations, nutrient imbalance and physiological disorders. Furthermore, drought causes a remarkable decrease in leaf numbers, relative water content, sugar yield, root yield, chlorophyll a and b and ascorbic acid concentrations. However, the concentrations of total phenolic compounds, electrolyte leakage, lipid peroxidation, amounts of proline, and reactive oxygen species are considerably increased because of drought stress. This negative impact of drought can be eliminated by using plant growth-promoting bacteria (PGPB). Under drought conditions, application of PGPB can improve plant growth by adjusting hormonal balance, maintaining nutrient status and producing plant growth regulators. This role of PGPB positively affects physiological and biochemical characteristics, resulting in increased leaf numbers, sugar yield, relative water content, amounts of photosynthetic pigments and ascorbic acid. Conversely, lipid peroxidation, electrolyte leakage and amounts of proline, total phenolic compounds and reactive oxygen species are decreased under drought in the presence of PGPB. The current review gives an overview on the impact of drought on plants and the pivotal role of PGPB in mitigating the negative effects of drought by enhancing antioxidant defense systems and increasing plant growth and yield to improve sustainable agriculture.

Two field experiments were conducted to evaluate the time of foliar application of 100 ppm salicylic acid (SA), two irrigation (IR) timings, three levels of spacing (SP) hill-1 with different plant density on growth, yield and quality characters of two sugar beet cultivars (‘Samba’ and ‘Farida’). The results revealed that the foliar application of 100 ppm SA at 30 days after planting (DAP) and 14 days after the first application significantly influenced top fresh mass and root biomass of sugar beet plants. Conversely, the increasing period between planting and first irrigation scheduling led to significant differences in fresh mass, sugar yield, and sucrose % as well as purity % of sugar beet. Plants density with 60 × 20 cm spacing hill-1 was found to be better than the other two spacings for major characters, particularly root fresh mass, and Total soluble solids and purity %. Inversely, spacing at 60 × 15 cm, between hills gave the maximum levels of top fresh mass, root yield and sugar yield in the first season. The interaction effect between spacing hill-1 at 60 × 20 cm and 100 ppm SA applied at 30 DAP gave the maximum levels of increment for most of the studied characters, particularly for cultivar ‘Farida’.

The impact of biochar and chitosan on barley plants under drought stress conditions was investigated during two field experiments. Our results confirmed that drought stress negatively affected morphological and physiological growth traits of barley plants such as plant height, number of leaves, chlorophyll concentrations, and relative water content. However, electrolyte leakage (EL%), lipid peroxidation (MDA), soluble sugars, sucrose and starch contents significantly increased as a response to drought stress. Additionally, 1000 grain weight, grains yield ha&minus, 1 and biological yield significantly decreased in stressed barley plants, also anatomical traits such as upper epidermis, lower epidermis, lamina, and mesophyll tissue thickness as well as vascular bundle diameter of flag leaves significantly decreased compared with control. The use of biochar and chitosan led to significant increases in plant height, number of leaves, and chlorophyll concentrations as well as relative water content, nevertheless these treatments led to significant decreases in electrolyte leakage (EL%) and lipid peroxidation (MDA) in the stressed plants. Moreover, anatomical and yield characters of stressed barley plants were improved with application of biochar and chitosan. The results proved the significance of biochar and chitosan in alleviating the damaging impacts of drought on barley plants.

The response of Egyptian wheat cultivars (Gemmeiza-7, Gemmeiza-10, Gemmeiza-11 and Gemmeiza-12) against leaf rust was studied at adult stage at two locations during two seasons. The results differentiated cultivars to susceptible and resistant depend upon the epidemiological parameters; FRS (%), AUDPC and r-value. The resistant cultivars, (Gemmeiza-10 and Gemmeiza-12) have the resistant genes; Lr10 and Lr19. However, Gemmeiza-7 and Gemmeiza-11 haven't any resistant genes. The discoloration of superoxide and hydrogen peroxide was decreased in moderately resistant and resistant cultivars compared to the susceptible cultivars. Also, electrolyte leakage increased in susceptible cultivars. Catalase and peroxidase activities were increased in resistant cultivars. Our results were confirmed with the anatomical studies which proved that epidermis thickness, mesophyll and phloem tissues were decreased in susceptible cultivars. Therefore, this explains why these cultivars still resistant till now.

A hydroponic experiment was carried out to investigate the effect of immersion durations (1 and 2h) of hydrogen peroxide on roots of strawberry (Fragaria x ananassa Duch.) grown under NaCl stress at (0, 34 and 68 mM NaCl). Roots immersion into H2O2 increased plant growth, photosynthetic pigment concentration, leaf relative water content and the activity of antioxidant enzymes i.e. (catalase, peroxidase and polyphenoloxidase) as well as decrease electrolyte leakage compared to untreated plants. High NaCl salinity level, induced ultrastructural alterations in leaflet mesophyll cells such as swelling thylakoids, disintegration of grana staking, increase number of plastoglobuli and starch grains as well as increase the size and number of mitochondria and its structure, shrinkage the plasma membranes, increase the Myelin-Like, membrane vesicles formation and increase the thickness of cell wall. In addition, roots immersion into H2O2 led to maintain the chloroplast structure, grana staking and increase the size of chloroplast and mitochondria, decrease the number and size of starch grains and plastoglobuli, decrease the number of membrane vesicles and peroxisomes, as well as maintain the cell wall structural and reduced its thickness. Furthermore, the high NaCl level led to increase the number of stomata and stomatal density and decreased the dimensions of stomatal pore. On the contrary, roots immersion into H2O2 decreases the stomatal density and its number. Concerning the leaflet anatomy, it was found that low NaCl salinity level increased the dimensions of midrib region, main vascular bundle as well as the thickness of palisade parenchyma. While, high salinity level, in most cases, decreased all these parameters. In conclusion, immersed roots of strawberry plants (pre-treatment) in H2O2 (1.0 M) for 1h application before exposure to salinity stress increased plant resistance and mitigated the deleterious effects of NaCl on cellular organelles.

Leaf rust caused by Puccinia triticina f. sp. tritici is the most common and wide-spread rust disease attacking many wheat cultivars in Egypt. Three main methods were used to identify leaf rust resistance genes; gene postulation, genetic analysis and molecular markers. The two resistant wheat cultivars i.e., Giza-171 and Sids-14, as well as the ten monogenic lines for leaf rust resistance; Lr9, Lr19, Lr21, Lr24, Lr25, Lr28, Lr29, Lr34, Lr46 and Lr47, were selected to carry out the present study. Out of the three methods used, genetic analysis and molecular markers were the best to identify the resistance genes in the two studied cultivars. Ten specific primers were used for the identification of 10 resistance genes in the two new Egyptian wheat cultivars i.e., Giza-171 and Sids-14. Six leaf rust resistance genes, Lr9, Lr25, Lr28, Lr29, Lr46 and Lr47 were identified in Giza-171, but only three genes, Lr29, Lr46 and Lr47, were detected in Sids-14. Each of these two new wheat cultivars proved to have an adequate and high level of genetic resistance to leaf rust. The tested wheat cultivars should be used as a good source of leaf rust resistance in breeding programs for rust resistance. Knowledge of the leaf rust resistance genes which has not been designated yet, will help to narrow the gap and throw light on the future objectives for the researchers interested in the full utilization of these genes in breeding materials.

Barley is a very important crop worldwide and has good impact in preserving food security. The impacts of 10 mM proline and 0.5 mM salicylic acid were evaluated on water stressed barley plants (Hordeum vulgare L. Giza126). Salicylic acid and proline treatments led to increased stem length, plant dry weights, chlorophyll concentration, relative water content, activity of antioxidant enzymes, and grain yield under drought stress. Nevertheless, lipid peroxidation, electrolyte leakage (EL), superoxide (O2&middot, ), and hydrogen peroxide (H2O2) significantly decreased in treated barley plants with proline and salicylic acid in both growing seasons as compared with drought treatment only, which caused significant decrease in stem length, plant dry weights, chlorophyll concentration, activity of antioxidant enzymes, as well as biological and grain yield. These results demonstrated the importance of salicylic acid and proline as tolerance inducers of drought stress in barley plants.

Salinity stress occurs due to the accumulation of high levels of salts in soil, which ultimately leads to the impairment of plant growth and crop loss. Stress tolerance-inducing compounds have a remarkable ability to improve growth and minimize the effects of salinity stress without negatively affecting the environment by controlling the physiological and molecular activities in plants. Two pot experiments were carried out in 2017 and 2018 to study the influence of salicylic acid (1 mM), yeast extract (6 g L&minus, 1), and proline (10 mM) on the physiological and biochemical parameters of sweet pepper plants under saline conditions (2000 and 4000 ppm). The results showed that salt stress led to decreasing the chlorophyll content, relative water content, and fruit yields, whereas electrolyte leakage, malondialdehyde (MDA), proline concentration, reactive oxygen species (ROS), and the activities of antioxidant enzymes increased in salt-stressed plants. The application of salicylic acid (1 mM), yeast extract (6 g L&minus, 1), and proline (10 mM) markedly improved the physiological characteristics and fruit yields of salt-stressed plants compared with untreated stressed plants. A significant reduction in electrolyte leakage, MDA, and ROS was also recorded for all treatments. In conclusion, our results reveal the important role of proline, SA, and yeast extracts in enhancing sweet pepper growth and tolerance to salinity stress via modulation of the physiological parameters and antioxidants machinery. Interestingly, proline proved to be the best treatment.

Cryptosporidiosis is caused by an opportunistic protozoan parasite (Cryptosporidium parvum and C. hominis) known as a parasite of humans, especially children and immunocompromised patients. The current study was designed to evaluate the therapeutic efficacy of a mixture of fig and olive leaf extracts as an alternative medicinal plant. Parasitological examination for oocysts in the stool and histopathological alterations in the small intestines were examined. Additionally, biochemical analyses of liver and kidney functions in addition to antioxidant parameters such as superoxide dismutase (SOD), glutathione peroxidase (GSH) and catalase (CAT) in the plasma were evaluated. Our results showed that marked reduction in oocysts shedding and amelioration in intestinal histopathological changes and hepatic or renal functions were detected in all treated groups compared to the control infected group. Additionally, the treated groups with tested extracts at ratios 1:3 and 1:5 showed a significant decrease in the number of oocysts compared to the other treated groups. Results exhibited a significant increase in the plasma SOD, CAT and GSH levels in treated groups compared to the infected control one. This study suggested that a mixture of fig and olive leaf extracts is a convenient promising therapeutic agent for Cryptosporidiosis.

The effect of bio-agent Bacillus subtilus, nano titanium dioxide (TiO2) and Zinc oxide (ZnO) as well as the combination compared with fungicide (Topas100) was investigated under laboratory (in vitro) and greenhouse conditions against powdery mildew disease caused by Podosphaera xanthii. Most of treatments were strong to inhibit the spore germination of P. xanthii. B. subtilus and B. subtilus + nano-Tio2 were the most effective followed by Topas100, B. subtilus + nano-ZnO, nano-ZnO and Nano-TiO2 compared with control. Most of treatments significantly reduced the disease symptoms and diseases severity (%) particularly bio-agent, nano-ZnO and combination of B. subtilus + nano-ZnO, however, the fungicide treatment showed the best inhibition. As a consequence of treatments histo-biochemical and growth parameters of cucumber were changed. Reactive oxygen species (hydrogen peroxide and superoxide) were accumulated early. Chlorophyll content, catalase, peroxidase, and polyphenol oxidase activities were increased under various treatments, however, electrolyte leakage (EL) was decreased. The growth characters e.g. plant height, leaves number, fresh and dry weight/plant was significantly improved because of treatments. Combined of B. subtilus and nano-Zinc oxide treatment was the best treatment and promising to be an alternative to fungicide, consequently, decreasing the environmental pollution, cost and harmful effect of fungicide on human health.

Water deficit stress is an abiotic stress that causes reductions in growth and yield of many field crops around the world. The present research was aimed to elucidate the mitigating efficiency of exogenous application of select osmoregulators and biostimulants, i.e., potassium dihydrogen phosphate, actosol® (humic acid), Amino more (amino acids), and Compound fertilizer, applied as a spray that reached both foliage and the soil, on growth characteristics, antioxidant capacity, and productivity of barley (Hordeum vulgare L. Giza123) under water deficit stress during two successive growing seasons of field experiments in Egypt. Water deficit resulted in stress as estimated by stress indicators and decreased growth and poor health and development as reflected in statistically significant decreases in chlorophyll a and b and major nutrient (NPK) levels in tissues, stem length, number of leaves, and fresh and dry mass as well as yield components such as spike length, grains per spike, biological yield, grain yield, and 1000-grain weight. As a response to water deficit stress, reactive oxygen species (ROS, i.e., superoxide and hydrogen peroxide) levels increased significantly resulting in lipid peroxidation and decreased membrane integrity and significant increases in antioxidant enzymes such as catalase (CAT), polyphenol oxidase (PPO), and peroxidase (POX). All four treatments alleviated the detrimental impacts of water deficit stress as evidenced by statistically significantly increased photosynthetic pigment concentration, tissue NPK levels, growth, and yield parameters compared to the water deficit-stressed control, while the stress responses were significantly reduced. The osmoregulators used either partially restored the growth and yield of osmotic-stressed barley plants or certain treatments enhanced them. All osmoregulators tested mitigated the adverse impacts of water deficit stress on barley plants, but the highest induction was found when plants were treated with actosol®. The beneficial effects of the osmoregulators tested were the strongest overall in the order actosol® ˃ potassium dihydrogen phosphate ˃ Amino more ˃ Compound fertilizer.

Potentially toxic elements (PTEs)-induced genotoxicity on aquatic plants is still an open question. Herein, a single clone from a population of water hyacinth covering a large distribution area of Nile River (freshwater) was transplanted in two drainage water resources to explore the hazardous effect of PTEs on molecular, biochemical and anatomical characters of plants compared to those grown in freshwater. Inductivity Coupled Plasma (ICP) analysis indicated that PTEs concentrations in water resources were relatively low in most cases. However, the high tendency of water hyacinth to bio-accumulate and bio-magnify PTEs maximized their concentrations in plant samples (roots in particular). A Random Amplified Polymorphic DNA (RAPD) assay showed the genotoxic effects of PTEs on plants grown in drainage water. PTEs accumulation caused substantial alterations in DNA profiles including the presence or absence of certain bands and even the appearance of new bands. Plants grown in drainage water exhibited several mutations on the electrophoretic profiles and banding pattern of total protein, especially proteins isolated from roots. Several anatomical deteriorations were observed on PTEs-stressed plants including reductions in the thickness of epidermis, cortex and endodermis as well as vascular cylinder diameter. The research findings of this investigation may provide some new insights regarding molecular, biochemical and anatomical responses of water hyacinth grown in drainage water resources.

The majority of the plants in the natural conditions are resistant to most of the incompatible pathogens (viral, fungal and bacterial infections). This phenomenon is called ״non-host resistance״. This type of resistance is very important however, not enough research was conducted to explain the mechanism of this type of resistance. When the authors inoculated several non-host plants with incompatible pathogens, levels of hydrogen peroxide (H2O2) and superoxide (O2.-) were increased and elevated early after inoculation. This phenomenon was found in tomato, datura, tobacco, cucumber, squash and Chenopodium which were inoculated with tobacco powdery mildew, Papaya ringspot virus (PRSV), cucumber powdery mildew, tobacco mosaic virus (TMV), tomato powdery mildew and PRSV, respectively. Interestingly that, when some hosts from those mentioned above were inoculated, each with its compatible pathogen, no accumulation of H2O2 and O2.- was occurred. The authors concluded that reactive oxygen species (ROS) mainly H2O2 and O2.- could have a key role in inhibiting or killing the pathogens early in the non-host plants. The authors recommend giving more attention to the application of H2O2 and O2.- either with direct application or with applying compounds which induce or produce ROS against phytopathogens.